Resonance enhancement of electron-phonon interaction in nanostructures

Abstract

The theory of electron-phonon interaction in quantum well is developed taking into account the influence of interface optical phonons. A detailed analysis of the dependence of polaron effective mass on the quantum well size and dielectric characteristics of barrier material is performed. It is shown that quasi-two-dimensional polaron may arise in narrow quantum wells. However, the interaction parameters are determined by effective mass of carriers in the quantum well and interface optical phonons frequencies. If the barriers are made of non-polar material, the polaron effective mass depends on the quantum well width. By increasing the quantum well width, a new mechanism of amplification of the electron-phonon interaction is realized. It occurs in the case of coincidence of the optical phonon energy with the energy of one of the electronic transitions. This leads to a nonmonotonic dependence of polaron effective mass on the quantum well width.